Lead Programmer, Architect and Deputy Product Owner

• Completing the conversion from zPDV to STEP
• Quality assurance of C++ and perl sources (automated and manual)
• Support in solving incidents / errors in testing
• Implementation of post-supply batch for supplementing payment path numbers
• Implementation of batch for distribution of SGB 2 information to zKT
• Support in replacing Solaris with Linux
• Upgrade from gcc 7.4 to gcc 9.3
• Programmatic generation of makefiles required for build from Borland projects
• Addition of funding with new attribute "travel costs internship indicator"
• Programmatic generation of xsd and wsdl files required for build from IDL files
• Product Owner representation
• Implementation of batch for one-time payment execution
• Implementation of generator for Liquibase files
• Implementation and support of regularly performed anonymization of production data extracts
• Support in migration from SLES 12 to SLES 15
• Support in introduction of mTLS
• Implementation of batch for transmitting deletion impulse to EDA BE
• Structuring of scripts directory
• Investigation of possibilities for introducing String-Latin
• Investigation and elimination of findings determined by CheckMarx
• Support with PAP recalculations and general change notifications
• Implementation of "minimal solution" for String-Latin
• Conversion of ERP interfaces from SOAP to Rest
• Support in planning implementation of various technical and professional topics (Registry Modernization Act, Cash Security, Training Costs, 2/4-Eyes Principle)

Consulting on blockchain and bitcoin topics

• Migration of E-Plus customers of Mobilcom-Debitel to O2
• Selection of customers and processing of data to and from E-Plus and O2
• Test data management for O2 migration
• Identification of services to be re-billed according to BNetzA requirements
• Matching and merging of roaming SMS partials for billing purposes
• Pseudonymization of customer data for test purposes according to EU-GDPR
• Consolidation of individual letters into mailings for postal service provider
• Comparison of DECOS and TCS systems against SAP (dealer commissions)
• Migration of klarmobil customers from MySQL to ApiOmat
• Performance tests with Gatling
• API Management with Apigee
• Coaching of customer data cleansing
• Production support
• Visualization of ApiOmat data
• Performance tuning of various processes
• Quality assurance through code review according to Clean Code principles
• Coaching on common Data Mining and Data Science procedures

Implemented optimization of roaming SMS contingent billing using agile rapid prototyping approach. Developed algorithm using Jaro-Winkler distance and custom logic to handle timestamp differences across time zones, enabling accurate matching and billing of previously problematic cases.

Developed efficient solution for BNetzA compliance checking using digital tree structure for longest matching prefix search, reducing database load and processing time significantly while handling billions of records.

• Technical consulting and development steering
• Re-design of field service interfaces and processing with implementation support
• Design and documentation of feedback systems
• 2nd and 3rd level support of collection software, especially field service orders and messages
• Quality assurance measures for new version deployments
• Error description and analysis, support in resolution, testing
• Creation of ad-hoc reports for business department

Redesigned critical interface to eliminate manual maintenance needs and error cases through improved business logic implementation.

• Quality assurance (bill-to-bill) of debitel billing system migration to Talkline
• Automation of data cleansing for ~100 million name and address records
• Migration of billing archive and unbilled usage of Talkline
• Preparation for Talkline billing system migration to Mobilcom
• Implementation of EU directives for roaming and SMS
• Creation of multiple CGIs for automating typical business transactions
• Performance tuning of various reports and processes

Implemented sophisticated data cleansing solution using Jaro-Winkler distance measurement, Daitch-Mokotoff phonetic search, and Damerau-Levenshtein distance neighborhood search algorithms for handling multilingual name variations.

• Quality assurance of inter-carrier billing
• Quality assurance of billing systems
• Design of GPRS Merge logic
• Quality assurance of telephony data conversion
• Development of tools for analyzing ASN.1 encoded data for 2nd/3rd level support
• Development of various QA tools for:
• Tracking auto-generated test calls from collection to data warehouse
• Efficient implementation of ASN.1 data filters
• Validating inter-carrier billing business rules implementation
• Near real-time visualization and monitoring of data streams
• Integration into client-specified infrastructure (multi-threaded client-server, Oracle)

Implemented efficient two-stage algorithm using Bloom filter and modified Horspool algorithm for searching phone numbers in billions of binary encoded records, achieving quasi-linear runtime performance.

• Design of BSP Trade workflow automation using Control-M (~30 interfaces, multiple daily operations, various batch processes including EOD)
• Implementation of ~300 Unix and dozen host scripts
• Administration of Microfocus COBOL Workbench 4.x
• Integration of Oracle ProCOB 1.x SQL precompiler
• Design of external securities trading participant integration

Implemented comprehensive automated workflow system enabling seamless integration of new back office with existing environments.